Flexible level editor

Modern, lightweight and efficient 2D level editor

Cross-Platform Level Editor

Realtime-CSG, CSG level editor for Unity

Work in progress prototype for the Chisel Level Editor, for Unity

A fully-featured Unity importer for LDtk (Level Designer Toolkit)

An open source alternative to Valve's Hammer Editor for the Goldsource engine. (No longer in development)

Dust Racing 2D is a traditional top-down car racing game including a level editor.

The open-source, cross-platform level editor for id Tech based games.

DarkRadiant is the map editor for The Dark Mod and other idTech4/Doom3-based games

Uses the collider of a PolygonCollider2D to generate a mesh for a Unity GameObject.

Advanced, but simple to use, runtime level editor for Unity.

A tilemap editor that aims to be simple, fast and lightweight.

Your Own Level Editor Creation Kit

Free procedural level generator for unity

Experimental level editor for Super Mario Odyssey (EditorCore plugin)

Unity level design plugin that adds support for Quake .MAP / Half-Life .RMF / Source .VMF, Q1 HL1 .WAD textures, and .FGD export.

A supercharged fork of the modern day level editor.

A set of modding tools (level editor, etc) for the Ratchet & Clank PS2 games.

Level editing suite for The Legend of Zelda: The Minish Cap